at 3.0:
	at now has a lex/yacc grammer, which is an extension of POSIX.2 to
	something more sensible.  There's an atd, which can still simulate
	atrun with the -s option.

at 3.1:
	Tried to fix some races in the atd code by renaming
	running jobs to "=" (thanks to aj@arthur.pfalz.de for
	pointing out the bug).

at 3.1.1:
	The last fix didn't work.  New locking scheme: as soon as
	a job starts, the file a00beef is hardlinked to =00beef.
	a00beef is unlinked as soon as actual shell execution
	starts.  "=" - files are deleted as soon as their job
	ends, or an hour after they should have run.

at 3.1.2:
	cleanups:  indent the source with OTBS
	remove output file if it already exists, with a warning.
	log attempts to run job twice
	added -b option to atd
	removed -b option from at (now batch calls "at -qb now")
	revamp run_loop so -b works correctly

at 3.1.3:
	Fixed "at 07:30" functionality for implicit tomorrow
	Include yywrap if none can be found

at 3.1.4:
	Set default batch maximum to 0.8
	Changed install group to 'root'

at 3.1.5:
	Merged Bjorn Helgaas' (helgaas@tomahawk.rsn.hp.com) patches:
		* Use setresuid(2) if setreuid(2) is not available
		  (HP-UX 10)
		* Use "chown user:group" instead of "chown user.group" for
		  HP-UX compatibility
		* RELINQUISH_PRIVS slightly earlier in at.c,
		  since it doesn't depend on
		* Change "volatile static" to "static volatile"
		* Test for HAVE_ATTRIBUTE_NORETURN instead of __GNUC__
		  in daemon.h
	Don't export SHELLOPTS (read-only variable in bash)

at 3.1.6:
	Made 'noon', 'teatime' and 'midnight' work.
	Reran autoheader so HP-UX compilation works.